Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.11.13 (protein kinase C)
 49,245 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have previously demonstrated that growth hormone (GH) promotes an increase in tyrosine kinase activity associated with the GH receptor. To gain insight into the role of GH-dependent tyrosine kinase activity in signaling by GH, we investigated the possibility that GH might stimulate MAP kinase, a serine/threonine/tyrosine kinase thought to be a common element in tyrosine kinase-initiated response cascades. Treatment of 3T3-F442A fibroblasts with 100 ng/ml GH results in a 3-6-fold increase in the ability of cell-free extracts to phosphorylate MAP-2 and myelin basic protein. GH-stimulated kinase activity is unaffected by heparin, H7, or cAMP-dependent protein kinase inhibitor peptide, partially reduced by staurosporin and inhibited by fluoride and calcium ions, indicating that the kinase is not protein kinase C or A, casein kinase, or a calcium/calmodulin-dependent protein kinase. Based on gel permeation chromatography, the molecular mass of the GH-stimulated MAP kinase is approximately kDa. Furthermore, anti-phosphotyrosine antibodies revealed the GH-dependent appearance of two phosphotyrosine-containing proteins in cell-free lysates of GH-treated cells that co-migrate with proteins recognized by anti-MAP kinase antibodies. The GH-dependent increase in MAP kinase activity displays a biphasic time course and is dependent on the concentration of GH applied to the cells. GH-dependent MAP kinase activity, partially purified by Mono-Q chromatography, is inactivated by treatment with alkaline phosphatase. Addition of H7 to the cells prior to the addition of GH has no effect, whereas addition of H8 increases MAP kinase activity in control cells with no effect in GH-treated cells, indicating that protein kinase C is unlikely to be an intermediary in the GH-dependent stimulation of MAP kinase activity. These findings indicate that signaling by GH in 3T3-F443A cells may, at least in part, utilize a kinase cascade similar to those that have been proposed for other membrane receptors with associated tyrosine kinase activity.
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PMID:Stimulation by growth hormone of MAP kinase activity in 3T3-F442A fibroblasts. 131 28

Nitric oxide (NO) is an important molecular messenger accounting for endothelial-derived relaxing activity in blood vessels, mediating cytotoxic actions of macrophages, and functioning as a neurotransmitter in the brain and periphery. NO synthase (NOS) from brain has been purified to homogeneity and molecularly cloned. We now report that NOS is stoichiometrically phosphorylated by cAMP dependent protein kinase, protein kinase C, and calcium/calmodulin-dependent protein kinase, with each kinase phosphorylating a different serine site on NOS. Activation of PKC in transfected cells reduces NOS enzyme activity by approximately 77% in intact cells and by 50% in protein homogenates from these cells. Utilizing fluorescence spectroscopy we find that purified monomer NOS contains 1 molar equivalent of both FMN and FAD. This stoichiometry is supported by enzymatic digestion of the flavins with phosphodiesterase, and titration of the FMN with a specific FMN binding protein. We demonstrate that purified NOS is labeled by a photoaffinity derivative of calmodulin. These recognition sites on NOS provide multiple means for regulation of NO levels and "cross-talk" between second messenger systems.
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PMID:Nitric oxide synthase regulatory sites. Phosphorylation by cyclic AMP-dependent protein kinase, protein kinase C, and calcium/calmodulin protein kinase; identification of flavin and calmodulin binding sites. 137 33

We have previously demonstrated that activation of protein kinase C (PKC) by phorbol esters induces selectively IgA synthesis by mouse B cells. In this study, we investigated the effects of a number of protein kinase inhibitors on IgA secretion induced by a recombinant murine IL-5 in LPS-stimulated mouse B cells. The results show that PKC inhibitors, such as sphingosine (SPH), staurosporine (STP) and H-7, blocked IL-5-induced IgA synthesis; the protein kinase A inhibitor HA-1004 and the inhibitor of calcium/calmodulin dependent protein kinase W-7 had no effect on IgA secretion induced by IL-5. The proliferation of the IL-5 sensitive B13 cell line in response to IL-5 was also inhibited by addition of SPH or STP or H-7. The data suggest an involvement of the PKC pathway in IL-5-induced B cell differentiation into IgA secreting cells.
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PMID:IL-5-induced IgA synthesis by LPS-stimulated mouse B cells is prevented by protein kinase C inhibitors. 158 1

The effects of the isoquinolinesulfonamide protein kinase inhibitors 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (H-7) and N-(2-guanidinoethyl)-5-isoquinolinesulfonamide (HA1004) on CA1 responses in hippocampal slices of the rat were examined to clarify their mode of action, and also to further define the role of Ca(2+) -dependent kinases in long-term potentiation. Initially, the inhibitory potencies of H-7 and HA1004 against both protein kinase C and type II Ca2+/calmodulin-dependent kinase were examined in standard in vitro phosphorylation assays. The apparent Ki values of H-7 and HA1004 for protein kinase C were 9 and 57 microM, respectively. In contrast, the Ki values of H-7 and HA1004 for type II calcium/calmodulin-dependent protein kinase were 156 and 13 microM, respectively. These results indicate that H-7 is a more effective inhibitor of protein kinase C, whereas HA1004 is a more effective inhibitor of type II calcium/calmodulin-dependent protein kinase. Following the induction of long-term potentiation, addition of 50 microM H-7 or HA1004 substantially increased the amplitude of the population spike in a control pathway, while producing no change or a slight increase in the spike amplitude in a previously potentiated long-term potentiation pathway. Moreover, H-7 (50 microM), but not HA1004, produced multiple population spikes in both pathways. Addition of a higher concentration of H-7 (300 microM) reduced the amplitude of the initial population spike but still produced multiple spikes. HA1004 (300 microM) typically produced effects similar to those observed with 50 microM H-7, increasing the amplitude of the control population spike and producing multiple spike activity in both pathways. In contrast to the differential concentration-dependent effects of H-7 on the population spike responses, qualitatively similar effects were observed at both low (50 microM) and high (300 microM) concentrations with regard to synaptic field responses. The initial slope of the population excitatory postsynaptic potential was significantly reduced by H-7, to a similar degree in both pathways. HA1004 produced a modest, but insignificant reduction in both pathways. These results, in conjunction with other reports, suggest that H-7 and HA1004 exert complex concentration-dependent effects with synchronously affect both excitatory and inhibitory synaptic transmission. We hypothesize that reduction of the population excitatory postsynaptic potential and spike (300 microM H-7) is due to reduction of excitatory inputs, whereas enhancement of the population spike amplitude (50 microM H-7) and the production of multiple spikes are due to the reduction of GABA-mediated inhibitory inputs.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Differential effects of isoquinolinesulfonamide protein kinase inhibitors on CA1 responses in hippocampal slices. 165 81

Calcium influx in response to extracellular signals can modulate gene transcription. A constitutive, calcium/calmodulin-independent mutant of type II calcium/calmodulin-dependent protein kinase was capable of increasing the transcription rate of specific genes independently of protein kinase C activation. This increase was mediated by transferable cis-active elements capable of binding the transcription factor CAAT/enhancer binding protein. Therefore, the activation of type II calcium/calmodulin-dependent protein kinase in response to stimuli that increase intracellular calcium is proposed to represent a distinct second messenger pathway in calcium-mediated regulation of gene transcription.
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PMID:Calcium/calmodulin-dependent protein kinase mediates a pathway for transcriptional regulation. 185 Aug 36

Tyrosine hydroxylase is activated and phosphorylated following treatment of PC-12 cells with bradykinin. In order to determine the mechanisms by which this occurs, we have evaluated the second messenger systems that may be responsible for this activation and phosphorylation. Inositol phosphates appear to play an important role in the activation and phosphorylation of tyrosine hydroxylase because bradykinin treatment significantly increased the formation of [3H]inositol phosphates and the concentration of intracellular free calcium ([Ca2+]i) in PC-12 cells. The uptake of extracellular 45Ca2+ into PC-12 cells at 1 min was significantly increased (107%) by bradykinin treatment and this increase was blocked by La3+, an inorganic calcium channel inhibitor, but not by nifedipine, an inhibitor of voltage-dependent calcium channels. The activation of tyrosine hydroxylase in PC-12 cells following bradykinin treatment was partially inhibited by La3+. Additivity experiments were performed to evaluate whether the activation and phosphorylation of tyrosine hydroxylase in PC-12 cells following treatment with bradykinin (10 microM) was similar to the activation and phosphorylation of tyrosine hydroxylase in PC-12 cells following treatment with dibutyryl cAMP (2 mM), 4 beta-phorbol-12 beta-myristate-13 alpha-acetate (PMA) (2 microM), and high K+ (56 mM). The combination of bradykinin and PMA produced additive effects, indicating that the activation of tyrosine hydroxylase by treatment with these two compounds was through different mechanisms. Furthermore, exposure of PC-12 cells to bradykinin did not increase intracellular cAMP levels. The combination of bradykinin and PMA treatments produced only partial additivity in tyrosine hydroxylase activity and phosphorylation. No additivity was produced with bradykinin and high K-treatment. Phosphopeptide analysis was performed on tyrosine hydroxylase obtained from PC-12 cells treated with bradykinin. Bradykinin treatment produced a significant incorporation of [32P]-phosphate into two phosphopeptides of tryptically digested tyrosine hydroxylase. One of these peptides corresponds to a peptide obtained by trypsinization of purified tyrosine hydroxylase that is phosphorylated by purified calcium/calmodulin-dependent protein kinase. The other 32P-tyrosine hydroxylase-peptide obtained from PC-12 cells treated with bradykinin corresponds to the phosphorylation site obtained during PMA stimulation of PC-12 cells. These results indicate that bradykinin treatment increases intracellular inositol phosphates, calcium, and possibly diacylglycerol levels in PC-12 cells. These effects could then increase calcium/calmodulin-dependent protein kinase activity and possibly calcium/phospholipid-dependent protein (protein kinase C) activity, resulting in increased phosphorylation and activity of tyrosine hydroxylase.
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PMID:Regulation of tyrosine hydroxylase activity in pheochromocytoma PC-12 cells by bradykinin. 196 17

The benzophenanthridine alkaloid chelerythrine is a potent, selective antagonist of the Ca++/phospholopid-dependent protein kinase (Protein kinase C: PKC) from the rat brain. Half-maximal inhibition of the kinase occurs at 0.66 microM. Chelerythrine interacted with the catalytic domain of PKC, was a competitive inhibitor with respect to the phosphate acceptor (histone IIIS) (Ki = 0.7 microM) and a non-competitive inhibitor with respect to ATP. This effect was further evidenced by the fact that chelerythrine inhibited native PKC and its catalytic fragment identically and did not affect [3H]- phorbol 12,13 dibutyrate binding to PKC. Chelerythrine selectively inhibited PKC compared to tyrosine protein kinase, cAMP-dependent protein kinase and calcium/calmodulin-dependent protein kinase. The potent antitumoral activity of celerythrine measured in vitro might be due at least in part to inhibition of PKC and thus suggests that PKC may be a model for rational design of antitumor drugs.
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PMID:Chelerythrine is a potent and specific inhibitor of protein kinase C. 224 23

Binding of [3H]-staurosporine to different protein kinases was time-dependent, reversible and saturable. Scatchard analysis of saturation isotherms indicated one class of binding sites for [3H]-staurosporine with dissociation constants (KD) of 9.6, 2.0, 3.0 and 7.4 nM for protein kinase C, cAMP-dependent protein kinase, tyrosine protein kinase and calcium/calmodulin-dependent protein kinase respectively. [3H]-staurosporine binding was fully displaced by unlabelled staurosporine or the related compound K-252a whereas other protein kinase inhibitors (H-7, H-8 and W-7) did not compete with [3H]-staurosporine. These data confirm that sataurosporine shows no selectivity for different protein kinases and suggest the putative existence of distinct, specific binding sites for [3H]-staurosporine on these enzymes.
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PMID:Characterization of specific binding sites for [3H]-staurosporine on various protein kinases. 239 90

Studies were conducted to determine if the protein kinase C inhibitor H-7 could block the effects of phorbol-12-myristate-13-acetate (PMA) on astrocyte morphology. Contrary to expectation, H-7 alone was found to induce morphological changes very similar to those elicited by PMA. This effect was shared by two other inhibitors of protein kinase C, H-8 and staurosporine, but not by the cyclic nucleotide-dependent protein kinase inhibitor HA-1004 or the calcium/calmodulin dependent protein kinase inhibitor W-7. Although the morphological effects observed with H-7 resemble those induced by PMA, H-7 did not promote the redistribution of protein kinase C to the membrane or induce the phosphorylation of endogenous proteins like PMA. In addition, the effects of H-7 were still observed in cells depleted of protein kinase C activity which were no longer responsive to treatment with PMA. Cytoskeletal elements appear to be involved in the effect of H-7 on cell shape since this effect is blocked by treatment with colchicine. Activators of the cyclic AMP-dependent protein kinase also alter astrocyte shape, however, while H-7 did cause a slight increase in cyclic AMP levels, it was unlikely that this action is responsible for its effect on morphology. One common action of both H-7 and PMA was to decrease the 32P content of several 20,000 Da proteins. While the mechanism by which H-7 exerts its influence on astrocyte morphology remains to be clarified, be it by the inhibition of protein kinase C or some other mechanism, the results suggest that caution must be used when interpreting the effects of activators and inhibitors of this kinase.
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PMID:Astrocyte morphology altered by 1-(5-isoquinolinylsulfonyl) 2-methyl piperazine (H-7) and other protein kinase inhibitors. 254 56

The phosphorylation of DNA topoisomerase II in Drosophila Kc tissue culture cells was characterized by in vivo labeling studies and in vitro studies that examined the modification of exogenous enzyme in total homogenates of these embryonic cells. Several lines of evidence identified casein kinase II as the kinase primarily responsible for phosphorylating DNA topoisomerase II. First, the only amino acyl residue modified in the enzyme was serine. Second, partial proteolytic maps of topoisomerase II which had been labeled with [32P]phosphate by Drosophila cells in vivo, by cell homogenates in vitro, or by purified casein kinase II were indistinguishable from one another. Third, phosphorylation in cell homogenates was inhibited by micrograms/ml concentrations of heparin, micromolar concentrations of nonradioactive GTP, or anti-Drosophila casein kinase II antiserum. Fourth, cell homogenates were able to employ [gamma-32P]GTP as a phosphate donor nearly as well as [gamma-32P]ATP. Although topoisomerase II was phosphorylated in homogenates under conditions that specifically stimulate protein kinase C, calcium/calmodulin-dependent protein kinase, or cAMP-dependent protein kinase, modification was always sensitive to anti-casein kinase II antiserum or heparin. Thus, under a variety of conditions, topoisomerase II appears to be phosphorylated primarily by casein kinase II in the Drosophila embryonic Kc cell system.
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PMID:Phosphorylation of DNA topoisomerase II in vivo and in total homogenates of Drosophila Kc cells. The role of casein kinase II. 284 38


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